﻿using GComp.Apps.EasyStock.Common;
using GComp.Apps.EasyStock.DataModel;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Split App template is documented at http://go.microsoft.com/fwlink/?LinkId=234228

namespace GComp.Apps.EasyStock {
    /// <summary>
    /// Provides application-specific behavior to supplement the default Application class.
    /// </summary>
    sealed partial class App : Application {
        /// <summary>
        /// Initializes the singleton Application object.  This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public App() {
            this.InitializeComponent();
            this.Suspending += OnSuspending;
        }

        private DataContext data;

        private void SetUp() {
            data = DataContext.Instance;
            if (!data.IsInitialized) {
                data.SetUp();
            }
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used when the application is launched to open a specific file, to display
        /// search results, and so forth.
        /// </summary>
        /// <param name="args">Details about the launch request and process.</param>
        protected override async void OnLaunched(LaunchActivatedEventArgs args) {

            SetUp();

            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active

            if (rootFrame == null) {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();
                //Associate the frame with a SuspensionManager key                                
                SuspensionManager.RegisterFrame(rootFrame, "AppFrame");

                if (args.PreviousExecutionState == ApplicationExecutionState.Terminated) {
                    // Restore the saved session state only when appropriate
                    try {
                        await SuspensionManager.RestoreAsync();
                    } catch (SuspensionManagerException) {
                        //Something went wrong restoring state.
                        //Assume there is no state and continue
                    }
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }
            if (rootFrame.Content == null) {
                // When the navigation stack isn't restored navigate to the first page,
                // configuring the new page by passing required information as a navigation
                // parameter
                if (!rootFrame.Navigate(typeof(GroupsOverview), "AllGroups")) {
                    throw new Exception("Failed to create initial page");
                }
            }
            // Ensure the current window is active
            Window.Current.Activate();
        }

        /// <summary>
        /// Invoked when application execution is being suspended.  Application state is saved
        /// without knowing whether the application will be terminated or resumed with the contents
        /// of memory still intact.
        /// </summary>
        /// <param name="sender">The source of the suspend request.</param>
        /// <param name="e">Details about the suspend request.</param>
        private async void OnSuspending(object sender, SuspendingEventArgs e) {
            var deferral = e.SuspendingOperation.GetDeferral();
            await TearDown();
            await SuspensionManager.SaveAsync();
            deferral.Complete();
        }

        private async Task<DataManager> TearDown() {
            return await DataContext.Instance.TearDown();
        }
    }
}
